Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.


  1. Advanced Patent Search
Publication numberUS5079005 A
Publication typeGrant
Application numberUS 07/362,033
Publication dateJan 7, 1992
Filing dateJun 5, 1989
Priority dateJun 17, 1988
Fee statusPaid
Publication number07362033, 362033, US 5079005 A, US 5079005A, US-A-5079005, US5079005 A, US5079005A
InventorsKashmiri L. Gupta
Original AssigneeGupta Kashmiri L
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Time release protein
US 5079005 A
Disclosed is a porous protein particle for delivering over a period of time an active ingredient impregnated therein, and methods of making and using the same. The protein particles have a median size less than about 50 microns. Active ingredient entrapped in the porous structure is gradually released from the protein particle.
Previous page
Next page
What I claim is:
1. A method for delivering an active ingredient over time, comprising the steps of:
a. providing a plurality of porous seed protein particles which differ from the naturally occurring seed protein in that at least a portion of the lipid materials naturally occurring in the seed have been removed from said particles, said particles having an active ingredient contained within the pores thereof in such a manner that it can migrate out of said pores, said particles having a median particle size sufficiently small that without said active ingredient, said particles are in the form of a free flowing powder; and
b. permitting the active ingredient to migrate out of the pores to provide a sustained release of the active ingredient over a period of at least 20 minutes.
2. A method as in claim 1 wherein the permitting step is responsive to a predetermined enabling event.
3. A method as in claim 2 wherein the enabling event is a change in pH.
4. A method as in claim 2 wherein the enabling event is a change in temperature.
5. A method as in claim 2 wherein the enabling event is exposure to ultraviolet light.
6. A method as in claim 2 wherein the enabling event is exposure to a solvent for the active ingredient.
7. The method of claim 1, wherein said active ingredient is lipopilic.
8. The method of claim 1, wherein said active ingredient is a pharmaceutical.
9. The method of claim 1, wherein said active ingredient is a cosmetic material.
10. The method of claim 1, wherein said active ingredient is a pesticide.
11. The method of claim 1, wherein said active ingredient is a pest repellant.

This application is a division of application Ser. No. 208,731, filed June 17, 1988, now U.S. Pat. No. 5,023,080.


The present invention relates to vehicles for delivering an active ingredient, and more particularly, to vehicles which release the active ingredient over a prolonged period of time.

Controlled release of an active ingredient over time has significant advantages in numerous applications over one or more bolus releases of the active ingredient. Sustained release over an extended period of time enables application of a lower overall dose of the active ingredient while minimizing wide concentration gradients which result from multiple bolus applications. For example, in the case of a cream having dermatologic activity, a greater than necessary concentration of the active ingredient must often be applied due to various factors such as dilution due to perspiration, UV-initiated degradation, or volatilization which reduce its efficacy. Thus, the concentration of the active ingredient may start out much higher than necessary, implicating toxic dose or allergy considerations, then decline through and below the effective dosage range. Flattening the dosage curve and extending the delivery time thereof through the use of time release vehicles can achieve significant advantages in many fields, including medicine, cosmetics, pesticides, herbicides, fertilizers and others.

Known time release vehicles generally fall into one of several categories. A first type of carrier comprises beads or droplets of active ingredient encapsulated in a polymeric coating designed to solubilize or rupture under predetermined circumstances to release the active ingredient. This first type of microencapsulation generally provides a bolus release of the active ingredient upon the occurrence of the predetermined event to rupture the membrane. For example, U.S. Pat. No. 3,786,123 to Katzen discloses encapsulation of nutrients in a high protein content vegetable composition which solubilizes in the environment of the digestive tract.

Another known microencapsulation technique, which achieves a more prolonged release of active ingredient over time, utilizes a microencapsulation coating or membrane which is either semi-permeable or porous to allow the active ingredient to diffuse out of the microcapsule.

A third type of vehicle comprises a porous matrix having an active ingredient dissolved or dispersed throughout. The delivery rate of the active ingredient is a function of the porosity of the structure, the solubility of the active ingredient, and other driving forces such as diffusivity responsible for liberating the active ingredient from the matrix. For example, U.S. Pat. No. 4,690,825 to Won discloses a time release delivery vehicle comprising a spherical polymeric bead having a network of pores with an active ingredient held within the network to provide controlled release of the active ingredient.

For some applications, however, the synthetic polymer bead carriers are disadvantageous. Microencapsulation in a polymeric bead or shell is typically achieved by adding the active ingredient to a monomer solution prior to or during the polymerization step. As the porous polymer structure is formed, active ingredient is entrapped within the pores. It is also possible that excess monomer can be trapped within the pores to be released with the active ingredient. The presence of monomer presents a potential health hazard. Synthetic polymer microencapsulation vehicles typically have the further disadvantage of imparting an undesirable gritty feel to topical creams made up for cosmetic and dermatologic applications. Regardless of the application, synthetic polymers used for microencapsulation are generally not biodegradable. Therefore, these polymers may not be used in powder forms if there is a possibility of inhalation. A small nondegradable particle, if inhaled, can present the possibility of serious health consequences if it remains in the body. In addition, some synthetic polymers can decompose to give off hazardous chemicals under certain circumstances. These problems limit the usefulness or detract from the desirability of synthetic polymers in a number of applications.


To overcome the foregoing disadvantages of prior art synthetic bead and shell delivery vehicles, there has been provided in accordance with one aspect of the present invention a time release delivery vehicle for delivering an active ingredient over time, which comprises a multiplicity of biodegradable porous protein particles, each having a network of pores with the active ingredient contained therein. The protein particles are usually irregular in shape, and are derived from natural grains and legumes such as canola, beans, oats, rapeseed and soya. In addition, the particle size is generally between about 1/10 micron to 50 microns. The porous delivery vehicle can further be provided with an outer encapsulating layer to prevent escape of any of the active ingredient from the pores of the delivery vehicle, until exposure to a predetermined triggering agent or event which will remove or render permeable the outer layer. Such an event could be a change in temperature or pH, exposure to ultraviolet light, or exposure to a solvent for the active ingredient such as perspiration.

In accordance with another aspect of the present invention, there has been provided a process of preparing a time release delivery vehicle for delivering an active ingredient over time. According to the process, a biodegradable protein concentrate (such as seed protein) having a porous structure is provided, and indigenous volatiles such as moisture are removed from the particulate to form a substantially dry powder. In most applications, the dried powder obtained after the removal of indigenous volatiles is then combined with the active ingredient under agitation so that the active ingredient will permeate the porous structure of the powder. The active ingredient may be dissolved in a suitable solvent, which solvent is removed later after impregnation of the particles with the active ingredient. The removal of solvent may not be necessary for some applications. An example of such a situation is entrapment of water, or an active ingredient dissolved in water.

The indigenous volatiles may be removed by any of a variety of known methods such as heating and/or vacuum drying, or removal by solvent extraction. The dried powder may then be combined with the active ingredient in any of a number of known ways, such as in a tumble dryer or using spouted bed or fluidized bed or spraydrying techniques. The resulting impregnated powder may be used dry, or be formulated into an emulsion or suspension with a medium suitable for any of a variety of cosmetic, pharmaceutical, or insecticide applications.

In accordance with a further aspect of the present invention, there has been provided a method of delivering an active ingredient over time, which includes the steps of providing a porous protein particle having an active ingredient therein and permitting the active ingredient to migrate out of the pores to provide a sustained release of the active ingredient. Commencement of the migration step can be made responsive to the occurrence of an enabling event which increases the solubility or diffusivity of the active ingredient. These events may occur at the application site as a result of change of one or more factors such as pH, temperature, moisture content, or mechanical perturbations.

Further features and advantages of the present invention will become apparent from the detailed description of preferred embodiments which follows.


FIG. 1 is a graph comparing evaporation rates of ethanol with encapsulated ethanol.

FIG. 2 is a graph comparing evaporation rates of isopropanol with encapsulated isopropanol.

FIG. 3 is a graph comparing evaporation rates of acetone with encapsulated acetone.

FIG. 4 is a graph comparing ethanol elution rates of four different impregnated protein concentrates.


The present invention provides a porous protein delivery vehicle for delivering an active ingredient over a prolonged period of time. The protein concentrate for use in the present invention comprise natural proteins. Preferred proteins are derived from grains or legumes such as canola, beans, oats, rapeseed, and soya.

A number of known processes exist for the preparation of a suitable protein powder for use in the present invention. For example, in U.S. Pat. No. 4,089,848 to Bell, the isolation of a proteinaceous fraction from oats is disclosed by extracting lipids from the comminuted oats with an organic solvent, carrying out alkaline and acid precipitation on the residue, and finally isolating the acid soluble protein. Oughton, in U.S. Pat. No. 4,154,728, describes another process for separating fractions of differing compositions from comminuted proteinaceous material from a variety of food sources including wheat, rye, barley, triticale, peas and buckwheat. The Oughton process comprises mixing the proteinaceous material with an aliphatic hydrocarbon or alcohol suitable to dissolve the lipids in the material. The wet slurry is distributed by means of centrifugation into fractions which differ primarily in protein composition. A similar process is applied to comminuted oats in U.S. Pat. Nos. 4,211,695 and 4,211,801 to Oughton.

To facilitate recovery of the protein in powder form from the slurry produced in accordance with the foregoing processes, U.S. Pat. Nos. 4,208,259 and 4,208,260 to Oughton disclose the application of an electric field to the mixture and collection of a comminuted oat fraction which clings to the anode. An improved method of recovery is disclosed in U.S. Pat. No. 4,407,841 to Boocock, comprising the addition of aqueous ethanol to the slurry to agglomerate the proteinaceous material and facilitate separation thereof.

The protein particles are separated to an approximate median particle size of less than 50 microns, and to as fine as 0.1 micron or less depending upon the desired end use of the carrier. For example, a larger particle size (and therefore a larger total pore volume and surface area) can result in a longer period of sustained release.

Because the powder is derived from natural grains and legumes, the particles will be irregular in shape, due to crushing and fragmenting during the milling process. However, median particle size can be determined by milling parameters or by using a series of graduated sieves or particle size analysis. Also because of their natural origin, the protein particles of the present invention are fully biodegradable, and there is no possibility of entrapped unreacted monomer to chemically interact with or be released with the active ingredient, nor are there harmful polymer degradation products that could be released.

Many suitable protein concentrates or protein powders are commercially available. For example, soya protein concentrate is available in 96% pure form from Protein Technologies International, St. Louis, Mo., USA. Great Northern White Bean protein concentrates are available from POS, Ltd., Saskatoon, Canada.

Several advantages are accrued through the use of a fine particulate of naturally occurring grain or seed proteins over prior art time release carriers. The protein particles of the present invention are typically smaller in size than the prior art synthetic polymer beads, and the protein particles are also somewhat resilient, whereas the synthetic porous beads known in the art are relatively rigid structures. As a result, creams and emulsions formulated using the carrier of the present invention exhibit an exquisitely smooth feel, compared to the gritty texture imparted by prior art porous beads. This is a particularly important feature for certain applications of the time release carrier, such as inclusion in formulations intended for cosmetic or dermatologic use.

The protein concentrate is advantageously dried prior to use as a carrier according to the present invention, to remove water and other indigenous volatiles which may otherwise reduce the available pore volume necessary for holding the active ingredient. In addition, depending upon the protein separation process, residual solvent could reside in the pores which could react adversely with the active ingredient.

Drying can be accomplished by any of a number of known methods, such as oven drying at elevated temperatures or subjecting the powder to a vacuum with or without the addition of heat. Alternatively, solvent extraction methods can be used, depending upon the particular requirements of the active ingredient and the end use of the carrier.

The dried protein concentrate is then impregnated with any of a variety of active ingredients which are desired for release over a prolonged period of time. The particular active ingredient to be used can vary widely, including such diverse applications as in cosmetics, pharmaceuticals, and insecticides. Volatiles can be entrapped, such as alcohol and various fragrance compounds. Various ingredients in cosmetics are suitable for entrapment, such as para amino benzoic acid (PABA) or its derivatives and PARSOL (a trademark of Bernel Chemical Company) or other active sunscreen ingredients, as well as moisturizing ingredients such as urea and mineral oil. Numerous dermatologically active materials are suitable for entrapment in the carrier of the present invention, including benzoyl peroxide, resorcinol and retinoic acid for acne, and a variety of deodorants. Additional pharmaceutically active ingredients can include antibiotics, fungicides, astringents, anti-inflammatory agents and antipruritics. Insecticides such as pyrethrins for flea control on pets can be entrapped in the carrier of the present invention, as well as numerous agriculturally related compositions such as herbicides, fungicides, fertilizers and insecticides. The foregoing are only illustrative of a few of the many ingredients that can be utilized with the protein particles of the present invention.

The quantity of the active ingredient to be entrapped will vary depending upon the desired dosage of active ingredient to be delivered in terms of either total volume or total elapsed delivery time, the viscosity and/or volatility of the active ingredient, and other parameters that will be apparent to one of skill in the art. Entrapped active ingredient can reach as high as 50% by weight of the solids, or more.

Entrapping or encapsulating the protein concentrate with an active ingredient may be accomplished by any of a variety of methods which can be envisioned by one of ordinary skill in the art. For example, the active ingredient may be sprayed into the powder in a liquid mist form while the powder is maintained in constant motion. The necessary motion can be achieved in any of a variety of commercially available tumble dryers or other equipment designed for agitating a powder. In addition, spouted bed dryers, fluidized bed dryers or other equipment which will be appreciated by one skilled in the art can be used. Alternatively, the active ingredient can be dissolved in a suitable solvent and the protein particles immersed in the resulting solution with or without agitation. The introduction of many active ingredients into the porous structure of the protein powder can be facilitated by performing the introduction step at elevated temperatures.

It is further anticipated that some nonactive ingredients such as surfactants (e.g. polysorbates) and cosolvents (e.g. alcohols) may be encapsulated to modify the release rates of the active ingredient. The change in release rates may be due to emulsification or dissolution of the active ingredient.

After sufficient active ingredient has permeated the structure of the protein powder, the agitation can be ceased and the material cooled. If a solvent was used to carry an active ingredient into the protein particle, that solvent can be evaporated by heating or exposing to a vacuum, or both, depending upon the thermal stability of the active ingredient.

The delivery vehicle of the present invention can be designed to commence the period of timed release of the active ingredient upon the occurrence of any of a variety of enabling events. This is useful to ensure an acceptable shelf life for the commercial product. For example, an active ingredient may solubilize when contacted with perspiration or other body fluid, in which case the solubility may become a part of the rate determining step. Alternatively, an active ingredient may solubilize or volatilize in response to a change in temperature or pH.

In a variation of the delivery vehicle of the present invention, an outer layer is provided to encapsulate the impregnated protein particle with an impermeable membrane, which may comprise either a solid or a liquid. In this embodiment, the period of controlled release will not commence until the membrane has been ruptured or dissolved. After the rupture or compromise of the outer membrane, the active ingredient will diffuse out of the delivery vehicle in the manner described supra. For example, a water soluble membrane may be formed by coating the particle with an aqueous solution of polyvinyl alcohol, and then drying to form a film.

Another encapsulation technique is disclosed in U.S. Pat. No. 3,786,123 to Katzen. Katzen discloses the encapsulation of an active ingredient in gelatinized corn flour. According to that method, the active ingredient was thoroughly admixed with the corn flour and the resulting admixture was extruded in an extruder manufactured by the Wenger Mixer Manufacturing Company of Sabetha, Kan. The extruder was operated at a pressure of 1,000 psi and a temperature of 240 F. This temperature was selected as sufficient to gelatinize the corn flour yet not deleteriously affect a selected active ingredient. The gelatinized corn flour completely enclosed individual or groups of particles of the active ingredient.

By utilizing this or another known encapsulation method, attributes of both the porous matrix and the microencapsulation systems can be combined. This is particularly useful, as described, when a certain shelf life or other prolonged period will be necessary before the active ingredient will be put to use.

Modification of Proteins

Several methods are available to modify the protein concentrate. These methods have been generally developed by protein chemists for peptide synthesis. These reactions are generally limited to carboxyl and amino groups in the alpha position. One such well-known method is that of Sheehan and Hess, J. Am. Chemical Soc. 77:1067 (1955). According to this method, the carboxyl group of the protein is activated by a water soluble carbodimide such as 3-ethyl-3-(3-dimethylaminopropyl) carbodimide. The carbodimide-activated intermediate is reactive. The activated group can be further reacted with methionine and tryptophan. Processes for using these modifications of soya protein are known and are described by Voutsinas and Nakai, J. Food Sci. 44:1205 (1979).

The carbodimide method and other protein derivitization methods can be used to attach molecules that affect the release rates of the active ingredient. Of course, the particular molecule attached will depend on characteristics of the active ingredient and the desired release profile. For example, lipid-type materials may be attached to slow the release of lipophilic active ingredients. Hydrogen bonding characteristics may also be used to slow release of appropriate active ingredients by attaching molecules to which the active ingredient will hydrogen bond. Ligand or chelating derivitizing molecules capable of releasably binding the active ingredient are similarly contemplated.

Protein concentrates modified by these methods can be used not only to tailor the rate of release, but also to achieve the necessary aesthetics for cosmetic and dermatological applications.

Alternatively, a delivery vehicle can be provided having a permeable outer membrane which will operate in addition to the porous protein structure as a further rate limiting structure. A number of membranes are feasible. These can range from an oil layer on the surface of the particles to surface coatings formed from polymers such as Polyvinyl alcohol, polyacrylates, and polysaccharides such as Dextran, Guar, Gum Arabic, etc. Some of these reagents may also be dispersed within the particles.

Selection of a particular outer membrane, whether permeable or nonpermeable, will likely be influenced by the intended use of the system. For example, in some pharmaceutical applications, an outer membrane will be selected which will impart desirable suspension characteristics, without introducing toxic or adversely reactive solvents.

The dried impregnated protein powder, with or without an encapsulating layer, can then be mixed with any of a variety of creams, gels, oils, lotions, or other media to form mixtures, emulsions or suspensions for cosmetic, pharmaceutical or other products. The powder can be mixed with other dry ingredients such as fillers and stabilizers if it is desired that the end product be delivered in dry form. Any of a variety of known pharmacologically acceptable excipients may additionally be utilized as the delivery medium for the impregnated powder.

Accordingly, the protein particle carrier of the present invention can be incorporated into any of a vast variety of media for bringing the impregnated particle into communication with the surface where the active ingredient is to be released. In the case of a medium having a solvent base, such as any of the creams, gels, oils, lotions, or other "wet" media, it is often desirable that the active ingredient be insoluble in the solvent of the media. In this manner, the active ingredient will not commence to discharge from the porous protein particle simply by virtue of its contact with the delivery medium. For example, in the case of a sunscreen application of the present invention, an active ingredient which is soluble in water and, hence, in perspiration, would optimally be incorporated into a cream or a lotion which is not water-based. If a water-based medium is nonetheless desirable for other reasons, then the protein particle can be encapsulated in an outer impermeable membrane which is designed to rupture or compromise under circumstances other than mere exposure to an aqueous environment.

Encapsulation and Release Rate Data

A number of active ingredients have been encapsulated using protein concentrates. The maximum amount of material entrapped depends on the characteristics of the active ingredient. In general, the maximum amount of active ingredient has been around 40% by weight of the dry solids. The experimental values for maximum loading are shown in Table 1. These ingredients are fully extractable with solvents.

              TABLE 1______________________________________           Maximum LoadingIngredient      Wt % Active Ingredient______________________________________Mineral Oil     40Parsol-MCX      40Pyrocide Technical 5192           40______________________________________ Note: ParsolMCX was obtained from Bernel Chemical Company of Engelwood, New Jersey. Pyrocide Technical 5192 was obtained from MGK of Minneapolis, Minnesota. Protein Concentrate from oats was used for this study.

The release rates from the particles are a function of the ingredients and the environment. The active ingredient can be released as a result of vapor diffusion to the atmosphere, liquid and/or vapor diffusion to surfaces such as skin and release due to chemical interaction or dilution. At present the experimental data is limited to vapor diffusion to the atmosphere. However, other studies are planned.

The release rates of volatile materials such as alcohols and solvents have been studied. Organic materials such as ethanol, isopropyl alcohol, butanol and acetone were used for this work. Three sources of protein concentrates have been used. The protein concentrates from Peas and Great Northern White Beans were obtained from POS, a contract research center in Saskatoon, Canada. Soya concentrate (PP660) containing 92% protein was obtained from Protein Technologies International of St. Louis, Mo. A protein concentrate from oats was prepared in our laboratory. The release rates were studied at room temperature, which was controlled around 22 C.

In all cases, a 1 gram sample of protein concentrate was mixed with 1 gram of organic material such as ethanol, acetone, etc. in an open glass petri plate (5 cm.). One gram of the organic material was also added to another similar petri plate. Both petri plates were left open to the atmosphere. The room temperature during these experiments was about 22 C. Each plate was weighed every few minutes using a Mettler PE1600 balance. The weight loss was calculated as a function of time. In some cases more than one solid was used for encapsulation. Even in these cases, the weight changes for the encapsulated material and the control were determined concurrently. This ensured uniformity of operating conditions.

The experimental data are represented graphically in FIGS. 1 to 4. In these graphs, the fractions I and II refer to protein concentrates from oats. The data show that the release rate is dependent on the ingredient encapsulated. The major effect on release rates is for the organics such as alcohols with reactive groups capable of forming significant association with carboxyl and/or amino groups of the proteins. The release rates are not significantly affected for solvents such as acetone, which do not form any significant association with protein particles under the atmospheric conditions. However, acetone release rates may be affected by modifying the structural properties of proteins in the concentrates. FIG. 4 indicates that the release rates are affected by the concentration of protein and its origin.

For the purpose of illustration, and not in any way to limit the applicable scope of the present invention, reference is made to the following examples.

The examples use a number of protein concentrates obtained from a research center (POS, Saskatoon, Canada) and International Protein Technologies of St. Louis, Mo. These concentrates contained 50-90% protein by weight. The particle size of these concentrates ranged from less than 1 micron to 10 microns. A protein concentrate from oats was prepared in our laboratory.

EXAMPLE 1 Sunscreen Lotion

PARSOL is a popular sunscreen chemical available from Bernel Chemical Company, Engelwood, N.J., and used in the preparation of sunscreen lotions. The maximum concentration of PARSOL is generally limited to about 6% by weight to minimize any allergic reactions. Entrapment of PARSOL in accordance with the present invention can reduce the concentration of the chemical in direct contact with the skin at any one time, yet permit an effective amount of the sunscreen agent to be present at any time during the active life of the lotion. Moreover, the active ingredient can be more stable in entrapped form, and absorption by the skin will be reduced. All of these factors will provide a sunscreen lotion which is more effective, longer lasting, and resulting in reduced skin irritation.

Extracted oat protein concentrate was prepared which was relatively free of any lipids and contained up to 40% protein. The protein concentrates were further dried in a convection oven for two hours at about 45-50 C. This procedure ensured that the protein concentrates were substantially free of volatile compounds such as water.

A 16-gram sample of PARSOL was weighed out into a beaker and mixed with 16 grams of isopropyl alcohol to fully dissolve the PARSOL. A 40-gram sample of oat protein concentrate was thereafter mixed with the alcohol-PARSOL mixture. The resulting mixture was homogenized by manual stirring for approximately 20 minutes, and was allowed to stand for an additional 30 minutes to ensure uniform penetration. The solvent was allowed to evaporate under a hood until a free flowing powder was obtained. The final powder contained about 30% PARSOL by weight. This powder was used to prepare a sunscreen lotion by combining it with mineral oil and isopropyl palmitate. Encapsulated powder showed better stability against UV light compared to PARSOL.

EXAMPLE 2 Sunscreen Lotion

The experiment described in Example 1 above was repeated, using a protein concentrate from Great Northern White Bean. This experiment again resulted in a free-flowing powder impregnated with PARSOL, which was used to make a sunscreen lotion.

EXAMPLE 3 Flea and Tick Powder

Synergerized pyrethrins are a common active chemical used for control of fleas on dogs. Pyrethrins are generally synergized with piperonyl butoxide. One such synergized material is marketed by McLaughlin Gormley King ("MGK") of Minneapolis, Minn. However, these chemicals have unpleasant smells and the life of the chemicals is relatively short after application.

Protein concentrate as described above was first dried in a convection oven for two hours at about 80-90 F. to remove most of the volatile components. A 4 gram sample of MGK pyroside intermediate 5192 was mixed with 6 grams of isopropyl alcohol. This mixture was thoroughly mixed for 30 minutes with the protein concentrate to allow permeation of the alcohol-pyroside intermediate 5192 mixture into the porous structure of the protein. The alcohol was thereafter allowed to evaporate while the mixture was continually stirred to maintain uniform dispersion of the active ingredient. The resulting powder showed much reduced odor. In addition, a test conducted at the University of California, Riverside indicated that the material is effective in extermination of roaches and fleas. The encapsulated pyrethrin showed better stability against UV light compared to unencapsulated pyrethrin.

EXAMPLE 4 Insecticide

Dursban is the trademark for an insecticide marketed by Dow Chemical Company. The major use of this chemical is for the environmental control of insects and roaches, and the chemical is characterized by a strong, unpleasant odor. Thus, Dursban was impregnated into the porous structure of a protein powder to reduce the odor while at the same time allowing a continuous effective release of the active ingredient.

A powdered protein concentrate from oats of the type previously described was allowed to dry in a convection oven at about 80-90 F. for about two hours. A 0.25-gram sample of Dursban was weighed into a beaker and mixed with 6 ml chloroform to fully dissolve the solids. A 100 gram sample of protein concentrate was thereafter introduced into the chloroform-Dursban solution under constant agitation to impregnate the protein concentrate. The mixture was stirred for 30 minutes at room temperature. Chloroform was thereafter allowed to evaporate under a hood while the mixture was maintained under constant agitation until a dry powder was obtained. The dried material was a free-flowing powder showing only faint odor, and it was found to be effective in killing German roaches. Moreover, the protein concentrate itself showed significant insecticidal activity. This may be due to disruption of the insects, protective cuticle layer.

Although this invention has been described in terms of certain preferred embodiments, other embodiments and applications that are apparent to those of ordinary skill in the art are also within the scope of this invention. Accordingly, the scope of the invention is intended to be defined only by reference to the appended claims.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US3116206 *Dec 22, 1961Dec 31, 1963Ncr CoEncapsulation process and its product
US3390050 *Jun 8, 1965Jun 25, 1968Ciba Geigy CorpStable pharmaceutical beads conaining medicament incorporated in synthetic copolymerby bead polymerization
US3496272 *Jan 23, 1968Feb 17, 1970American Home ProdEster of 3-(2-propynyloxy)-estradiol
US3516941 *Jul 25, 1966Jun 23, 1970Minnesota Mining & MfgMicrocapsules and process of making
US3663687 *Jun 26, 1968May 16, 1972Minnesota Mining & MfgBiodegradable parenteral microspherules
US3720534 *May 25, 1970Mar 13, 1973Moore Business Forms IncPolymer gels and method of making same
US3786123 *Jan 25, 1971Jan 15, 1974S KatzenMethod for stabilizing and preserving nutrients and products
US3885052 *Nov 9, 1973May 20, 1975Ralston Purina CoProcess of producing a soy product having improved sorption
US3886084 *Aug 23, 1971May 27, 1975Champion Int CorpMicroencapsulation system
US3985298 *Nov 1, 1974Oct 12, 1976Moleculon Research CorporationControlled release materials and method of use
US3989649 *Jun 3, 1975Nov 2, 1976Showa Denko Kabushiki KaishaProcess for production of spherical porous fillers for liquid chromatography by suspension polymerization of monovinyl and polyvinyl aromatic monomers in the presence of paraffin wax
US4089848 *Feb 2, 1976May 16, 1978Du Pont Of Canada LimitedExtraction of protein food values from oats
US4110529 *Nov 20, 1975Aug 29, 1978Ceschoslovak Akademie VedMethod of manufacturing spherical polymer particles from polymer solutions
US4154728 *Dec 6, 1976May 15, 1979Du Pont Of Canada, Ltd.Process for the treatment of comminuted proteinaceous material
US4208259 *May 3, 1979Jun 17, 1980Du Pont Of Canada, LimitedTreatment of comminuted oats under the influence of an electric field
US4208260 *May 3, 1979Jun 17, 1980Du Pont Of Canada, LimitedTreatment of comminuted proteinaceous material under the influence of an electric field
US4211695 *Jan 26, 1979Jul 8, 1980Du Pont Of Canada, LimitedProcess for the treatment of comminuted oats
US4211801 *Sep 28, 1978Jul 8, 1980Du Pont Of Canada LimitedProcess for the treatment of comminuted oats
US4230687 *May 30, 1978Oct 28, 1980Griffith Laboratories U.S.A., Inc.Encapsulation of active agents as microdispersions in homogeneous natural polymeric matrices
US4232047 *May 30, 1978Nov 4, 1980Griffith Laboratories U.S.A., Inc.Food supplement concentrate in a dense glasseous extrudate
US4307201 *Jun 18, 1980Dec 22, 1981Diamond Shamrock CorporationHighly adsorptive macroporous polymers
US4322311 *Apr 25, 1980Mar 30, 1982Damon CorporationProcess for producing controlled porosity microcapsules
US4324683 *Aug 20, 1975Apr 13, 1982Damon CorporationEncapsulation of labile biological material
US4353809 *Mar 10, 1980Oct 12, 1982Fuji Photo Film Co., Ltd.Process for the production of microcapsules
US4353888 *Dec 23, 1980Oct 12, 1982Sefton Michael VEncapsulation of live animal cells
US4353962 *May 18, 1981Oct 12, 1982Environmental Chemicals, Inc.In-flight encapsulation of particles
US4366310 *Dec 10, 1980Dec 28, 1982Euroceltique, S.A.Controlled release compositions
US4388352 *Aug 3, 1981Jun 14, 1983Board Of Regents, University Of WashingtonMethod for preparing a controlled release composition
US4391909 *May 1, 1981Jul 5, 1983Damon CorporationMicrocapsules containing viable tissue cells
US4396670 *Mar 24, 1981Aug 2, 1983The Wiggins Teape Group LimitedProcess for the production of microcapsules
US4401456 *Apr 28, 1981Aug 30, 1983The United States Of America As Represented By The Secretary Of AgricultureControlled release of bioactive materials using alginate gel beads
US4407841 *Oct 28, 1981Oct 4, 1983Du Pont Canada Inc.Recovery of a proteinaceous oat fraction from a dispersion thereof in hydrocarbon solvent
US4407957 *Apr 28, 1982Oct 4, 1983Damon CorporationReversible microencapsulation of a core material
US4439488 *Feb 26, 1982Mar 27, 1984The United States Of America As Represented By The Secretary Of AgricultureEncapsulation by entrapment within polyhydroxy polymer borates
US4444699 *Apr 20, 1982Apr 24, 1984Appleton Papers Inc.Capsule manufacture
US4464271 *Nov 30, 1983Aug 7, 1984International Flavors & Fragrances Inc.Liquid or solid fabric softener composition comprising microencapsulated fragrance suspension and process for preparing same
US4518580 *Mar 30, 1984May 21, 1985American Cyanamid CompanyExpanded corncob grits having increased absorptivity and a method for the preparation thereof
US4522953 *Sep 24, 1984Jun 11, 1985Lever Brothers CompanyLow density porous cross-linked polymeric materials and their preparation and use as carriers for included liquids
US4576826 *Dec 21, 1981Mar 18, 1986Nestec S. A.Process for the preparation of flavorant capsules
US4581378 *Feb 10, 1982Apr 8, 1986United Agri Products, Inc.Rodenticide compositions comprising an artificial sweetener and a rodenticide
US4615880 *Apr 12, 1984Oct 7, 1986Ceskoslovenska Akademie Ved Of PragueDressing for wounds and the method for manufacturing thereof
US4690682 *Jan 14, 1986Sep 1, 1987Damon Biotech, Inc.Sustained release
US4690825 *Oct 4, 1985Sep 1, 1987Advanced Polymer Systems, Inc.Method for delivering an active ingredient by controlled time release utilizing a novel delivery vehicle which can be prepared by a process utilizing the active ingredient as a porogen
US4707355 *Jan 22, 1985Nov 17, 1987The Dow Chemical CompanyMicroencapsulated insecticidal bait formulations as fumigants
US4828836 *May 19, 1987May 9, 1989Euroceltique S.A.Controlled release pharmaceutical composition
CH573212A5 * Title not available
EP0061701A2 *Mar 23, 1982Oct 6, 1982Wickhen Products, Inc.A solid entrapped emollient-moisturizer composition and the use thereof
EP0171457A1 *Aug 17, 1984Feb 19, 1986The Wellcome Foundation LimitedComposition for the controlled discharge of an active ingredient, and its preparation
Non-Patent Citations
1 *Elliott P. Barrett, et al., The Journal of the American Chemical Society, vol. 73, pp. 373 380 (1951).
2Elliott P. Barrett, et al., The Journal of the American Chemical Society, vol. 73, pp. 373-380 (1951).
3 *John Coe, et al., A New Natural Ingredient for Cosmetic Formulators, pp. 48 56 (1973).
4John Coe, et al., A New Natural Ingredient for Cosmetic Formulators, pp. 48-56 (1973).
5 *Sheehan, and Thess, The Journal of the American Chemical Society, vol. 77, p. 1067 (1955).
6 *Stephen Brunauer, et al., The Journal of the American Chemical Society, vol. 60, pp. 309 319 (1938).
7Stephen Brunauer, et al., The Journal of the American Chemical Society, vol. 60, pp. 309-319 (1938).
8 *Voutsinas, and Nakai, J. Food. Sci., vol. 44, p. 1205 (1979).
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US5456917 *Jan 12, 1994Oct 10, 1995Cambridge Scientific, Inc.Method for making a bioerodible material for the sustained release of a medicament and the material made from the method
US5552135 *Feb 25, 1993Sep 3, 1996Estee Lauder, Inc.Sunscreens containing plant extracts
US5817608 *Aug 26, 1996Oct 6, 1998Brimms Inc.Cleansing compositions containing conditioning agents and refined agricultural grains
US5879712 *Jun 7, 1995Mar 9, 1999Sri InternationalMethod for producing drug-loaded microparticles and an ICAM-1 dosage form so produced
US5888500 *Sep 26, 1996Mar 30, 1999Marshall; Lucia G. I.Biological control agent biocarriers and method of formation
US5945099 *May 4, 1998Aug 31, 1999Marshall; Lucia G. I.Mycoherbicidal delivery compositions, preparation and methods for controlling aquatic weeds
US6030639 *May 23, 1996Feb 29, 2000The Liposome Company, Inc.Treatment using prostoglandin and particulate formulations
US6319693Jun 7, 1995Nov 20, 2001Leadd B.V.Cloning of chicken anemia virus DNA
US7087245Apr 22, 2002Aug 8, 2006Bomberger David CICAM-1 formulation having controlled-size microparticles
US8263108Jun 21, 2002Sep 11, 2012Durect CorporationZero-order prolonged release coaxial implants
US8834934Feb 11, 2004Sep 16, 2014Haviland Products CompanyMaterial encapsulation system
US8889174Aug 20, 2012Nov 18, 2014Durect CorporationZero-order prolonged release coaxial implants
US9034257Oct 27, 2009May 19, 2015Nodality, Inc.High throughput flow cytometry system and method
US9183237Nov 26, 2012Nov 10, 2015Nodality, Inc.Methods and apparatus related to gate boundaries within a data space
US20030007992 *Jun 21, 2002Jan 9, 2003Southern Biosystems, Inc.Zero-order prolonged release coaxial implants
US20030091649 *Apr 22, 2002May 15, 2003Bomberger David C.ICAM-1 formulation having controlled-size microparticles
US20060058206 *Nov 3, 2003Mar 16, 2006Venture Management AllianceAqueous activated components conveyed in a non-aqueous carrier system
US20060110464 *Feb 11, 2004May 25, 2006Walls John EMaterial encapsulation system
US20060127425 *Dec 10, 2003Jun 15, 2006Venture Management Alliance, LlcEncapsulated material released to generate perceivable sensorial indicia of discrete event occurrence
US20090269800 *Apr 29, 2009Oct 29, 2009Todd CoveyDevice and method for processing cell samples
US20100014741 *Jul 10, 2009Jan 21, 2010Banville Steven CMethods and apparatus related to gate boundaries within a data space
US20100030719 *Aug 10, 2009Feb 4, 2010Covey Todd MMethods and apparatus related to bioinformatics data analysis
US20100042351 *Jul 10, 2009Feb 18, 2010Covey Todd MMethods and apparatus related to management of experiments
US20100076414 *Oct 28, 2009Mar 25, 2010Searete LlcRemote control of substance delivery system
US20100105074 *Oct 27, 2009Apr 29, 2010Nodality, Inc. A Delaware CorporationHigh throughput flow cytometry system and method
EP2075256A2Jan 14, 2003Jul 1, 2009William HermanMultispecific binding molecules
U.S. Classification424/408, 424/65, 424/405, 424/499, 424/76.4, 424/490, 424/419
International ClassificationA61Q17/04, A61Q17/02, A61L9/04, A01N25/26, A61K8/64, A61K9/16, A01N25/10, A61K8/04
Cooperative ClassificationA61K9/1658, A01N25/10, A61L9/042, A01N25/26, A61K2800/56, A61K8/0279, A61Q17/02, A61K8/645, A61L9/04, A61Q17/04
European ClassificationA61K8/02N6, A61L9/04B, A61K8/64C, A61Q17/02, A01N25/10, A61L9/04, A01N25/26, A61K9/16H6H, A61Q17/04
Legal Events
Aug 17, 1992ASAssignment
Effective date: 19920610
Jul 7, 1995FPAYFee payment
Year of fee payment: 4
Aug 3, 1999REMIMaintenance fee reminder mailed
Jan 7, 2000SULPSurcharge for late payment
Jan 7, 2000FPAYFee payment
Year of fee payment: 8
Dec 31, 2001ASAssignment
Effective date: 20011115
Jul 31, 2002ASAssignment
Effective date: 20020422
Jan 17, 2003ASAssignment
Effective date: 20030109
Effective date: 20030109
Jun 10, 2003FPAYFee payment
Year of fee payment: 12
May 11, 2006ASAssignment
Effective date: 20060501
Nov 14, 2006ASAssignment
Effective date: 20061030
Jan 16, 2007ASAssignment
Effective date: 20061027
Jan 30, 2007ASAssignment
Effective date: 20061027
Mar 13, 2007ASAssignment
Effective date: 20061027